Market adoption of wireless LAN (WLAN) technology has exploded, as users from a wide range of backgrounds and vertical industries have brought this technology into their homes, offices, and increasingly into the public air space. This inflection point has highlighted not only the limitations of earlier-generation systems, but the changing role WLAN technology now plays in people's work and lifestyles, across the globe. Indeed, WLANs are rapidly changing from convenience networks to business-critical networks. Increasingly users are depending on WLANs to improve the timeliness and productivity of their communications and applications, and in doing so, require greater visibility, security, management, and performance from their network.
As enterprises and other entities increasingly rely on wireless networks, the capabilities of wireless clients and the uses to which they are put increasingly expand. For example, certain wireless clients, such as laptops and even cell phones with WLAN capabilities, use wireless connections to access the wired computer network and make telephone calls, or engage in other interactive sessions involving multimedia elements, such as voice, video, graphics, and the like. Voice-over-IP (VoIP), for example, describes facilities for managing the delivery of voice information using the Internet Protocol (IP). In general, this means sending voice information in digital form in discrete packets rather than in the traditional circuit-switched protocols of the public switched telephone network. In addition to IP, VoIP uses the real-time protocol (RTP) to help ensure that packets get delivered in a timely way, and uses the Session Initiation Protocol (SIP) to set up the session implementing the call.
Many real-time network applications, such as video conferencing, involve multiple data streams, each corresponding to a different network data or traffic type, such as voice/audio data, video data and the like. Simulation results with IEEE 802.11e networks have shown that when a mixture of voice and data traffic is simulated, the voice traffic, because of its highest priority pushes data back and as a result the AP is able to achieve higher number of voice calls. However, this comes at the cost of decreased throughput and increased delay and jitter of the data traffic. Accordingly, video traffic can suffer the same fate while competing with voice traffic. While it is possible to adjust the Enhanced Distributed Channel Access (EDCA) parameters of the VI and VO class to strike a balance between voice capacity and how much the video suffers, it is believed that it could lead to statistical underutilization of resources if the new parameters do not capture the needs of various applications. Video conferencing is one such application where correlation of audio and video stream is important for purposes of lip-synchronization.
In light of the foregoing, a need in the art exists for methods, apparatuses and systems directed to the synchronization of traffic streams over IEEE 802.11 or other wireless local area networks or links. Embodiments of the present invention substantially fulfill this need.